Bug 1303728 - Seeing VM crash while writing in same RBD Disk from different VMs
Summary: Seeing VM crash while writing in same RBD Disk from different VMs
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Ceph Storage
Classification: Red Hat Storage
Component: RBD
Version: 1.3.2
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: rc
: 1.3.4
Assignee: Jason Dillaman
QA Contact: ceph-qe-bugs
URL:
Whiteboard:
Depends On: 1223652
Blocks:
TreeView+ depends on / blocked
 
Reported: 2016-02-01 19:09 UTC by Tanay Ganguly
Modified: 2017-07-30 15:36 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2017-06-28 15:46:34 UTC
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Ceph Project Bug Tracker 14595 0 None None None 2016-02-01 23:12:25 UTC

Description Tanay Ganguly 2016-02-01 19:09:46 UTC
Description of problem:
While trying to write on a same RBD image, the VM is getting crashed.

Version-Release number of selected component (if applicable):
rpm -qa | grep ceph
ceph-common-0.94.5-4.el7cp.x86_64
ceph-osd-0.94.5-4.el7cp.x86_64
ceph-0.94.5-4.el7cp.x86_64
ceph-radosgw-0.94.5-4.el7cp.x86_64
ceph-debuginfo-0.94.5-4.el7cp.x86_64
ceph-selinux-0.94.5-4.el7cp.x86_64

Selinux as enforcing.

How reproducible:


Steps to Reproduce:
1. Create an rbd image with --feature 13, create snap and clone it.
2. Attach the same Clone to 2 different VMs.
3. Try to write on the RBD clone from 2 different VMs at same time
   Used dd to write it.

Actual results:
Lock should handle this use case, and there should not be a crash

Expected results:
Seeing the VM Crash.

Additional info:
Logs attached.

Comment 2 Ken Dreyer (Red Hat) 2016-02-03 17:19:08 UTC
I discussed this with Jason and Josh, and the outcome is that we want to land a fix in 0.94.7 upstream and give it plenty of testing before pulling it downstream.

This is not technically a valid use case of RBD exclusive locking, and customers should never have two VMs using the same RBD image at the same time. If customers had such a setup, this would certainly cause other issues. Jason and Josh also confirmed that there's no way to hit this with a single client, nor during a VM live migration between hypervisors.

Since this is a lower priority bug, re-targeting to RHCS 1.3.3.

Comment 4 Jason Dillaman 2017-06-26 17:02:58 UTC
This was resolved in RHCS 2.x


Note You need to log in before you can comment on or make changes to this bug.